Froth Flotation Processes

ABSTRACT

Froth flotation processes that include adding a beneficiating amount of a value mineral collector composed of an organic ammonium salt of a sulfur-containing acid to at least one stage of a froth flotation process to recover value minerals from mineral ore bodies are disclosed herein.

CROSS-REFERENCE To RELATED APPLICATIONS

This application claims benefit of priority from U.S. ProvisionalApplication No. 61/548,417 filed Oct. 18, 2011 the content of which isincorporated herein by reference in its entirety. This application isalso related in subject matter to U.S. Provisional Application No.61/548,402 filed Oct. 18, 2011; and to U.S. Provisional Application No.61/548,408 filed Oct. 18, 2011.

BACKGROUND OF THE INVENTION

1. Field

The disclosed subject matter relates generally to compositions andprocesses used in the recovery of value minerals from mineral orebodies. More particularly, the disclosed subject matter relates to frothflotation processes that utilize an organic ammonium salt of asulfur-containing acid as a value mineral collector.

2. State of the Art

Froth flotation is a widely used process for beneficiating orescontaining valuable minerals, often referred to as “value minerals”.Value mineral(s) refer to the metal, metals, mineral or minerals thatare the primary object of the flotation process, i.e., the metals andminerals from which it is desirable to remove impurities.

A typical froth flotation process involves intermixing an aqueous slurrythat contains finely ground ore particles with a frothing or foamingagent to produce a froth. Ore particles that contain the valuemineral(s) are preferentially attracted to the froth because of anaffinity between the froth and the exposed mineral on the surfaces ofthe ore particles. The resulting beneficiated minerals are thencollected by separating them from the froth. Chemical reagents, referredto as “collectors,” are commonly added to the froth flotation process toeffect the separation. Certain theory and practice indicates thatsuccess of a flotation process for base metal sulfide and precious metalores is dependent on the collectors which impart selectivehydrophobicity to the value mineral separated from other minerals. See,e.g., U.S. Pat. No. 4,584,097, the entirety of which is incorporated byreference herein.

Other reagents, such as “frothers”, may be added to the process toprovide a suitable basic froth phase to capture hydrophobic valueminerals and facilitate separation and recovery thereof. Certain otherreagents, referred to as “modifiers”, may be used to enhance separationand recovery of the desired minerals and/or metals. Modifiers, which caninclude pH regulators, may be used to modify and control the pH of theore pulp in order to enhance separation and recovery of the desiredminerals and/or metals. In some instances, compounds referred to as“activators,” such as copper sulfate, may be used to activate a certainvalue sulfide mineral in order to enhance collector coating on thissulfide mineral.

Froth flotation is especially useful for separating finely ground valueminerals from the associate gangue or for separating value minerals fromone another. Because of the large scale on which mining operations aretypically conducted, and the large difference in value between thedesired minerals and the associated gangue, even relatively smallincreases in separation efficiency provide substantial gains inproductivity. Additionally, the large quantities of chemicals used inmining and mineral processing pose a significant challenge in terms ofhealth and safety to humans and the environment. Consequently, theindustry is continually searching for effective alternatives thatincrease safety while lessening the impact on the environment.

Currently, a large variety of organic sulfur-containing compounds, suchas xanthates, dithiophosphates, dithiocarbamates, etc, are utilized ascollectors in the flotation recovery of value minerals from sulfide andprecious metal ores. Existing thought about such compounds is thateither the free acid or any salt of the acid can be used in flotation,and that all the salts and free acid are equivalent, and obtainsubstantially the same result. Moreover, most of the collectors based onorganic sulfur-containing salts are aqueous and are the sodium orpotassium salts of sulfur-containing acid. Thus, when names ofcollectors are mentioned, such as a xanthate or dithiophosphate, it isin reference to a sodium or potassium salt.

A commonly used collector, xanthic acid, is an ionic compound that isproduced and transported as solid sodium or potassium salts of xanthicacid and is used as aqueous solutions at the mine site. While they haveshown value in mining processes, xanthates oxidize and hydrolyze in thepresence of water thereby releasing hazardous byproducts, and causingreduction in metallurgical performance, such as reduction in valuemineral recovery and/or grade. Solid xanthate can pose a fire hazard.Other common water-soluble ionic collectors pose similar hazards to avarying degree and display reduced metallurgical performance. Anadditional hazard is when such aqueous collectors are mixed with othercollectors, some toxic gases may be generated, or precipitates can beformed, which reduce the activity of the available collector or formsome other undesirable reaction products, all of which also causereduced metallurgical performance.

Many current collector and formulations thereof do contain water, whichreduces the available active collector and contributes significantly totransportation costs. Given the recent increase in fuel costs,cost-effective transportation and energy savings are important indeveloping alternatives to current collectors.

In view of the foregoing, there is a need in the art to develop a stablecollector formulation that offers improved metallurgical performance,cost savings, as well as reductions in hazards to humans and theenvironment. The inventors of the instant invention believe the subjectmatter disclosed and claimed herein is an answer to those needs.

SUMMARY OF THE INVENTION

The value mineral collectors composed of organic amine salts of organicsulfur-containing acids as described herein are practical, economicallyattractive and environmentally friendly alternatives compared to aqueousionic collectors such as alkali metal salts of organic sulfur-containingacids. Consequently, the collector compositions of the present inventionoffer many advantages including easier handling, as well as reducedcosts to ship the compositions to remote metallurgical plants. As shownin more detail below, the collector compositions of the presentinvention surprisingly exhibit improved recovery of value minerals.

Accordingly, in one aspect the present invention is directed to frothflotation processes for recovering value minerals from mineral orebodies by: adding a beneficiating amount of a collector to at least onestage of a froth flotation process, wherein the collector is an organicprimary or secondary ammonium salt of a sulfur-containing acid selectedfrom the group consisting of hydrocarbyl dithiophosphoric acids,hydrocarbyl monothiophosphoric acids, mercaptobenzothiazoles,hydrocarbyl xanthic acids, hydrocarbyl dithiocarbamic acids, hydrocarbylthioglycolic acids and hydrocarbyl trithiocarbonic acids.

In a further aspect, the present invention is directed to frothflotation processes for recovering at least one value mineral from amineral ore body, the steps including: grinding an ore containing atleast one value mineral to form ground ore; forming a slurry comprisingthe ground ore; intermixing an effective amount of at least one valuemineral collector as described herein with at least one of the groundore, the slurry, and combinations thereof; generating a froth with theslurry; and recovering the at least one value mineral from the froth.

These and other objects, features and advantages of this invention willbecome apparent from the following detailed description of certainembodiments of the invention taken in conjunction with the accompanyingExamples.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS OF THE INVENTION

The disclosed subject matter generally relates to processes andcollectors, used in the recovery of value minerals from an ore. Ingeneral, ores contain, inter alia, both “value” and “non-value”minerals. In this context, “value” mineral(s) refer to the metal,metals, mineral or minerals that are the primary object of the flotationprocess, i.e., the metals and minerals from which it is desirable toremove impurities. Examples of metals of interest include, but are notlimited to, gold, silver, copper, cobalt, nickel, lead, zinc,molybdenum, and platinum group metals, such as platinum and palladium,as well as combinations thereof. The term “non-value” mineral refers tothe metal, metals, mineral or minerals for which removal from the valuemineral is desired, i.e., impurities in the value mineral. A non-valuemineral is not necessarily discarded, and may be considered a valuemineral in a subsequent process.

While any ore may be subjected to the processes and the collectorsdescribed herein, the disclosed subject matter typically pertains tobase metal sulfide ores and precious metal ores. Examples of such oresinclude, but are not limited to, Cu—Mo ores, Cu—Au ores, primary Auores, platinum group metal (PGM) ores, Cu ores, Ni ores, and complexpolymetallic ores containing Pb, Zn, Cu and Ag.

In one embodiment, the collector includes an organic ammonium saltcompound according to Formula I:

where:

AN— is an anion from an organic sulfur-containing acid selected from thegroup consisting of hydrocarbyl dithiophosphoric acids, hydrocarbylmonothiophosphoric acids, mercaptobenzothiazoles, hydrocarbyl xanthicacids, hydrocarbyl dithiocarbamic acids, hydrocarbyl thioglycolic acidsand hydrocarbyl trithiocarbonic acids; R^(a) is a hydrocarbyl groupcomprising from 1 to 16 carbon atoms, optionally substituted with a —OHgroup and/or with one or more —(YR′)_(n)—YR″ groups, wherein n=0 to 3, Yis O, NR′″ or S, R′ is an alkylene or arylene group containing from 1 to12 carbon atoms, R″ and R′″ are, each independently, hydrogen or ahydrocarbyl group containing from 1 to 12 carbon atoms; and R^(b) ishydrogen or a hydrocarbyl group comprising from 1 to 16 carbon atoms,optionally substituted with a —OH group and/or with one or more—(YR′)_(n)—YR″ groups, wherein n=0 to 3, Y is O, NR′″ or S, R′ is analkylene or arylene group containing from 1 to 12 carbon atoms, R″ andR′″ are, each independently, hydrogen or a hydrocarbyl group containingfrom 1 to 12 carbon atoms; and wherein R^(a) and R^(b) may be linked toform a cyclic compound.

The organic sulfur-containing collector is derived fromsulfur-containing organic acids that contain at least one ionizable —SHor —OH group attached to a carbon atom or a phosphorus atom. Theammonium salt is a primary or secondary organic ammonium salt.

In one preferred embodiment, the collector is substantially free ofwater and substantially fee of inorganic salts. The phrase“substantially free of water” encompasses compositions that include lessthan 10% water by weight. For instance, compositions that would beconsidered to be substantially free of water can include less than 10%water by weight, e.g., 7% wt.; 5% wt.; 4% wt.; 3.5% wt, 3.0% wt., 2.75%wt., 2.5% wt., 2.0% wt., 1.5% wt., 1.0% wt., 0.5% wt., 0.1% wt., 100ppm, and the like.

The phrase “substantially free of inorganic salts” as used hereinencompasses collector compositions that include less than 5% inorganicsalt by weight. For instance, collector compositions that would beconsidered to be substantially free of inorganic salt can include lessthan 5% inorganic salt by weight, e.g., 4% wt.; 3.5% wt, 3.0% wt., 2.75%wt., 2.5% wt., 2.0% wt., 1.5% wt., 1.0% wt., 0.5% wt., 0.1% wt., 100ppm, and the like.

As used herein, the terms “hydrocarbyl group”, “hydrocarbon group”,“hydrocarbyl” and “hydrocarbon”, encompass compounds containing hydrogenand carbon atoms, optionally substituted with one or more groups such as—OH groups and/or with one or more —(YR′)_(n)—YR″ groups, wherein n=0 to3, Y is O, NR′″ or S, R′ is an alkylene or arylene group containing from1 to 12 carbon atoms, R″ and R′″ are, each independently, H or ahydrocarbyl group containing from 1 to 12 carbon atoms. As used herein,the pluralized version of acid, i.e., acids, indicates that thecompounds can be substituted or unsubstituted. The term “substituted” asused herein encompasses the replacement of one element, such ashydrogen, by another atom or a group containing one or more atoms or aheteroatom or a group containing one or more heteroatoms.

In some embodiments of the organic ammonium cation of the collectoraccording to Formula I, the R^(a) group is a hydrocarbyl groupcontaining 1-16 carbon atoms, optionally substituted by an —OH group.However, it is contemplated that the R^(a) group may also be ahydrocarbyl group containing 1-10 carbon atoms or a hydrocarbyl groupcontaining 1-6 carbon atoms, optionally substituted by an —OH group.R^(a) is preferably an alkyl group or an aryl group, and more preferablyan alkyl group. R^(a) is more preferably an alkyl group containing 1 to6, most preferably 1 to 4 carbon atoms.

The R^(b) group of the organic ammonium cation may be hydrogen or ahydrocarbyl group containing 1-16 carbon atoms, optionally substitutedwith one or more groups such as —OH groups and/or with one or more—(YR′)_(n)—YR″ groups, wherein n=0 to 3, Y is O, NR′″ or S, R′ is analkylene or arylene group containing from 1 to 12 carbon atoms, R″ andR′″ are, each independently, H or a hydrocarbyl group containing from 1to 12 carbon atoms.

In certain embodiments, R^(b) is hydrogen.

In another embodiment, R^(b) is a hydrocarbyl group containing 1-10carbon atoms, more preferably containing 1-6 carbon atoms. R^(b) ispreferably an alkyl group containing 1 to 10, more preferably 1 to 6 andmost preferably 1 to 4, carbon atoms.

The organic ammonium cation (N⁺H₂R^(a)R^(b)) of Formula I may beselected from dihydrocarbyl amines and monohydrocarbyl amines, andmixtures thereof. The organic ammonium cation (N⁺H₂R^(a)R^(b)) ofFormula I preferably has a molecular weight that does not exceed 200,more preferably not exceeding 150, and most preferably not exceeding130. The organic ammonium cation (N⁺H₂R^(a)R^(b)) of Formula Ipreferably has a molecular weight of at least 32.

Specific examples of ammonium salts include, but are not limited to,methylammonium, ethylammonium, propylammonium, butylammonium,ethanolammonium, diethanolammonium, propanolammonium,dipropanolammonium, dimethylammonium, diethylammonium, dipropylammonium,dibutylammonium, ethylenediammonium, 1,3-diammonium propane,hexamethylene diammonium, diethylenetriammonium, diphenylammonium salts,and mixtures thereof.

In certain embodiments, the organic sulfur-containing acid of thecollector is selected from hydrocarbyl dithiophosphoric acids,hydrocarbyl monothiophosphoric acids, hydrocarbyl xanthic acids,hydrocarbyl thioglycolic acids and hydrocarbyl trithiocarbonic acids.

Hydrocarbyl dithiophosphoric acids are generally according to thegeneral formula

wherein R1 and R2 are hydrocarbyl groups with the proviso that R1 and R2may be linked to form a cyclic compound. R1 and R2 are preferably andare each independently C2-C12 hydrocarbyl groups. Preferably, R1 and R2are independently C2-C8 hydrocarbyl groups, more preferably C2-C4hydrocarbyl groups. Examples of specific dihydrocarbyl dithiophosphoricacids include diisobutyl dithiophosphoric acid, diethyl dithiophosphoricacid, diisoamyl dithiophosphoric acid, diisopropyl dithiophosphoricacid, dicresyl dithiophosphoric acid, di-sec-butyl dithiophosphoricacid, di-2-ethylhexyl dithiophosphoric acid, ethyl sec-butyldithiophosphoric acid, and ethylamyldithiophosphoric acid.

Hydrocarbyl monothiophosphoric acids are generally according to thegeneral formula

wherein R1 and R2 are each independently a C2-C12 hydrocarbyl group,with the proviso that R1 and R2 may be linked to form a cyclic compound.Preferably, R1 and R2 are each independently a C2-C8 hydrocarbyl group,more preferably C2-C4 hydrocarbyl groups. Examples of specifichydrocarbyl monothiophosphoric acids include diisobutylmonothiophosphoric acid, diethylmonothiophosphoric acid, diisoamylmonothiophosphoric acid, diisopropyl monothiophosphoric acid, dicresylmonothiophosphoric acid, di-sec-butyl monothiophosphoric acid,di-2-ethylhexyl monothiophosphoric acid and ethyl sec-butylmonothiophosphoric acid.

Hydrocarbyl dithiocarbamic acids are usually selected from the group ofdihydrocarbyl dithiocarbamic acids and monohydrocarbyl dithiocarbamicacids and are generally according to the general formula:

wherein R1 is H or a C1-C12 hydrocarbyl group and R2, independently, isa C1-C12 hydrocarbyl group, with the proviso that R1 and R2 may belinked to form a cyclic compound. Preferably, R1 and R2 areindependently H or a C2-C8 hydrocarbyl group. More preferably, R1 and R2are independently H or a C2-C4 hydrocarbyl group. Examples includediisobutyl dithiocarbamic acid, di-n-butyl dithiocarbamic acid, diethyldithiocarbamic acid, diisopropyl dithiocarbamic acid, dibenzyldithiocarbamic acid, diphenyl dithiocarbamic acid, dioctyldithiocarbamic acid, monobutyl dithiocarbamic acid, monoethyldithiocarbamic acid, butyl phenyl dithiocarbamic acid, ethyl butyldithiocarbamic acid and the like.

Hydrocarbyl xanthic acids are generally according to the generalformula:

wherein R1 is a C2-C12 hydrocarbyl group. Preferably, R1 is a C2 to C5hydrocarbyl group. Examples of specific hydrocarbyl xanthic acidsinclude ethyl xanthic acid, n-butyl xanthic acid, isobutyl xanthic acid,n-propyl xanthic acid, isopropyl xanthic acid, sec butyl xanthic acid,n-amyl xanthic acid, isoamyl xanthic acid, 2 ethyl-hexyl xanthic acid,phenyl xanthic acid, benzyl xanthic acid.

Hydrocarbyl trithiocarbonic acids are generally according to the generalformula

wherein R1 is a C2-C12 hydrocarbyl group. Preferably, R1 is a C4-C12hydrocarbyl group. Examples of specific hydrocarbyl trithiocarbonicacids include butyl trithiocarbonic acid and dodecyl trithiocarbonicacid.

Hydrocarbyl thioglycolic acids are generally according to the generalformula

wherein R1 is a C2-C12 hydrocarbyl group. Preferably, R1 is C4 to C8hydrocarbyl group. Examples of specific hydrocarbyl thioglycolic acidsinclude butyl thioglycolic acid, octyl thioglycolic acid, and dodecylthioglycolic acid.

Mercaptobenzothiazoles are generally according to the general formula

wherein R1 is H or a —O—(C1-C12 hydrocarbyl) group or a C1-C12hydrocarbyl group. Preferably, R1 is a H or a C1 to C6 hydrocarbylgroup. Examples of specific mercaptobenzothiazoles include 6-hexyl2-mercaptobenzothiazole and 6-ethoxy 2-mercaptobenzothiazole. Preferredmercaptobenzothiazoles are selected from 2-mercaptobenzothiazole and6-hydrocarbyl-2-mercaptobenzothiazoles.

In a preferred embodiment, the organic sulfur-containing collector isselected from the group consisting of primary and secondary ammoniumsalts of hydrocarbyl dithiophosphoric acids, hydrocarbylmonothiophosphoric acids and hydrocarbyl xanthic acids. Particularlypreferred are the primary and secondary ammonium salts of hydrocarbyldithiophosphoric acids.

Examples of the collectors composed of an organic ammonium salt of anorganic sulfur-containing acid, include, but are not limited to,dimethylammonium salt of diisobutyl dithiophosphoric acid, ethylammoniumsalt of diisobutyl dithiophosphoric acid, diethylammonium salt ofdiisobutyl dithiophosphoric acid, diethanolammonium salt of diisobutyldithiophosphoric acid, diethylammonium salt of isobutyl xanthic acid,methylammonium salt of monothiophosphoric acid, dimethylammonium salt ofdiisobutyl monothiophosphoric acid, methylammonium salt of ethyl xanthicacid, methylammonium salt of isoamyl xanthic acid, ethylammonium salt ofbutyl trithiocarbonic acid, dimethylammonium salt of butyltrithiocarbonic acid, methylammonium salt of butyl thioglycolic acid,dimethylammonium salt of isopropyl xanthic acid, dimethylammonium saltof mercaptobenzothiazole, ethylammonium salt of mercaptobenzothiazole,hexamethylene diammonium salt of mercaptobenzothiazole,diethanolammonium salt of mercaptobenzothiazole, dimethylammonium saltof diethyl dithiocarbamic acid, diethylammonium salt of diethyldithiocarbamic acid, ethylammonium salt of diethyl dithiocarbamic acid,hexamethylene diammonium salt of N-propyl N-ethyl dithiocarbamic acid,and diethanolammonium salt of N-allyl, N-ethyl dithiocarbamic acid.

The compounds of organic ammonium salt of an organic sulfur-containingacid as described herein prove useful as value mineral collectors andmay be used in methods for recovering at least one value mineral from anore. In general, the organic ammonium salts of the organicsulfur-containing acids are utilized as collectors in froth flotationprocesses by adding a beneficiating amount of the collector (i.e., anamount of collector sufficient to effectively separate the valueminerals from the non-value minerals) to one or more stages of the frothflotation process.

The collector compositions described herein may be added to the frothflotation processes as the organic ammonium salt of an organicsulfur-containing acid or they may be part of a composition additionallyincluding one or more compound useful for froth flotation. In general,the collectors according to the present invention as described hereinare present in the collector composition in amounts and ratios that areeconomically feasible as well as effective to the recovery of the valueminerals. The amount of collector as described herein present in thecollector composition can vary from about 1 wt. % to about 99 wt. %based on the total weight of the collector composition. In oneembodiment, the amount of collectors as described herein present in thecollector composition is between about 30 wt. % and about 70 wt. % basedon the total weight of the collector composition.

Besides the collectors described herein, in some embodiments, thecollector compositions may optionally include one or more othercollectors different from the primary and secondary ammonium salts ofthe organic sulfur-containing acids according to the invention asdescribed herein. Such other collectors can be any known collectors,such as anionic collectors and neutral collectors.

In general, the primary and secondary ammonium salts of thesulfur-containing collectors that are described above display excellentphysical compatibility with neutral (so-called oily collectors)collectors. The physical stability of collector compositions thatinclude the collector according to the invention as herein described,together with a neutral collector allows them to be handled in an easymanner. Moreover, such collector compositions are chemically stable anddo not release toxic gases or fumes and do not require the use ofhazardous diluents and coupling agents.

As alluded to above, in some embodiments, the collector compositionsaccording to the present invention may optionally include one or moreadditives. Many such additives are known to those of skill in the frothflotation art and need not be further described in detail herein.Certain additives may include, for example, one or more of hydrocarbonoils, surfactants, aliphatic alcohols, glycols, glycol ethers andnon-aqueous solvents. Combinations of the foregoing additives are alsocontemplated.

The amount and type of additives present in the collector compositionwill vary depending on one or more of the following variables: the typeof collectors, the amount of the collectors, the type of ore, the valuemineral, and the like, and combinations thereof. The person of ordinaryskill in the art will be able to determine such values based on no morethan routine experimentation. In one embodiment, the total amount ofadditives present in the collector composition is between about 1 wt. %and about 95 wt. % based on the total weight of the collectorcomposition. In another embodiment, the total amount of additivespresent in the collector composition is between about 1 wt. % and about50 wt. % based on the total weight of the collector composition.

One example of a froth flotation process includes crushing an ore toform crushed ore (referred to herein as the “pre-grinding” or the“pre-grind” stage), and then grinding the crushed ore particles in agrinding mill to form ground ore. A slurry of water and ground ore isformed. The steps of grinding the ore and forming the slurry may becollectively referred to as the “grinding stage”. The slurry containingthe ground ore is then sent to the “conditioning stage” where the groundore is conditioned in a conditioner. The ground ore is subjected to aflotation process by passing air through the slurry in flotation cellsor a bank of flotation cells to cause flotation of the desired mineralsin a froth. The desired minerals, i.e., the value minerals, arecollected (“recovered”) from the froth in launders (referred to as the“flotation stage”).

As one of ordinary skill in the art will appreciate, a froth flotationprocess may include more than one stage of grinding, conditioning andflotation. Thus, the flotation concentrate from the first stage(referred to as “roughers” or “rougher-scavengers”) may be groundfurther and refloated in a circuit referred to as “cleaners”. Thecleaners may subject the concentrate of the first stage to furthergrinding, conditioning and flotation stages. Alternatively, theconcentrate from the first stage may be refloated without furthergrinding.

The tails from the cleaners may be refloated in a circuit referred to as“cleaner-scavengers”. It is envisioned that the disclosed subject matterencompasses addition of froth phase modifiers, monovalent ion modifierenhancing agents and collector compositions at any stage of the process,i.e., addition of the froth phase modifier (and/or monovalent ionmodifier enhancing agent and/or collector) in some instance may be doneuntil the second (or third) grinding stage, conditioning stage, orflotation stage.

Flotation reagents, which include the organic ammonium salts of anorganic sulfur-containing collectors described herein as well as, forexample, frothers, pH regulators, froth phase modifiers, dispersants,depressants, and the like, may be added to the crushed ore, ground oreand/or slurry, during the process at any or all of the stages of thefroth flotation process. Typically the flotation reagents, such as theorganic ammonium salts of the sulfur-containing collectors, especiallythose according to Formula I, described herein, are added to the frothflotation process at one or more stages of the process. For example, theorganic ammonium salt of a sulfur-containing collector may be added tothe grinding stage, the conditioning stage, or a combination thereof.The term “added” or any variation thereof, as used herein, means anymethod that can be used to bring two or more items or compounds togetherand encompasses intermixing, mixing, combining, incorporating, blendingand the like. Similarly, the term “intermixed” or any variation thereof,as used herein, means any method that can be used to bring two or moreitems or compounds together and encompasses adding, intermixing, mixing,combining, incorporating, blending and the like.

The organic ammonium salt of the sulfur-containing collectors describedherein are added to processes for recovering a value mineral from an orein an amount that is effective (“effective amount” or “beneficiatingamount”) to recover the value mineral. The effective amount of theorganic ammonium salt of the sulfur-containing collector may depend on avariety of factors, including the process used, the ore used, thecontents of the organic ammonium salt of the sulfur-containingcollector, and the like. In one embodiment the effective amount of theorganic ammonium salt of a sulfur-containing collector added to theprocess is from about 0.5 gram per ton (g/t) to about 500 g/t. Inanother embodiment, the effective amount of the organic ammonium salt ofa sulfur-containing collector added to the process is from about 1 g/tto about 200 g/t. In yet another embodiment, the effective amount of theorganic ammonium salt of a sulfur-containing collector added to theprocess is from about 2 g/t to about 100 g/t. In still a furtherembodiment, the effective amount of the organic ammonium salt of asulfur-containing collector added to the process is from about 5 g/t toabout 50 g/t. In another embodiment, the effective amount of the organicammonium salt of a sulfur-containing collector is from about 5 g/t toabout 20 g/t.

The organic ammonium salts of sulfur-containing collectors describedherein, or the collector compositions containing them, are typicallyadded to processes in a liquid form. Some of the compositions, whenmanufactured, can be in a solid form, but these can be readily made intoliquid form by dissolving in a suitable solvent or diluent.

Besides the organic ammonium salts of the sulfur-containing collectorsdescribed herein, or the collector compositions containing them, othercollectors can be added to the froth flotation process separately orsimultaneously.

EXAMPLES

The following examples are provided to assist one skilled in the art tofurther understand certain embodiments of the present invention. Theseexamples are intended for illustration purposes and are not to beconstrued as limiting the scope of the various embodiments of thepresent invention.

Unless otherwise specifically noted, the following notations are used inthe Examples below: “percent,” “%”, “weight %” and “wt. %” denotesweight percent, “g” denotes gram, “° C.” denotes degrees Celsius, “g/t”denotes gram per ton, “min” denotes “minutes”, “rec” and “Rec” denoterecovery of value mineral in concentrate, “S rec” represents the totalrecovery of all the sulfide minerals, “coll” stands for collector, “rpm”stands for revolutions per minute, “kg” is kilogram, “ppm” is parts permillion on a mass basis (also equal to g/t), “ml” is milliliter, and “L”is liter.

Example 1 Preparation of Ethylammonium Salt of DiisobutylDithiophosphoric Acid

Preparation of ethylammonium salt of diisobutyl dithiophosphoric acid isas follows: 130 grams (0.54 mole) of diisobutyl dithiophosphoric acid ischarged into a jacketed pressure reactor. The system is bubbled throughwith nitrogen for 20 min and 26 grams (0.58 mole) of liquefiedethylamine is added to the addition funnel and the entire system is thensealed under nitrogen. Then, with the system monitored by a pressuregauge and thermometer, ethylamine is added drop wise. The reactiontemperature is kept under 50° C. and pressure under 10 pounds per squareinch (“psi”). After the addition is over, the system is brought to 50°C. through the jacket by a heating circulator. The reaction temperatureis kept at 50° C. for 1 hour. The product is then discharged. The acidnumber (normally below 30) and iodine number (between 40-44) weremeasured to check the acidity and percent dithiophosphoric acid. Theproduct purity (ranging between 88-95%) is measured by liquidchromatography-mass spectrometry (“LC-MS”) and nuclear magneticresonance (“NMR”).

Example 2 Preparation of Diethylammonium Salt of DiisobutylDithiophosphoric Acid

Preparation of diethylammonium salt of diisobutyldithiophosphoric acidis as follows: 130 grams (0.54 mole) of diisobutyl dithiophosphoric acidis charged into a jacketed pressure reactor. The system is bubbledthrough with nitrogen for 20 min and 43 grams (0.58 mole) ofdiethylamine is added to the addition funnel and the entire system isthen sealed under nitrogen. Then, with the system monitored by apressure gauge and thermometer, diethylamine is then added drop wise andthe reaction temperature kept under 50° C. and pressure under 10 psi.After the addition is over, the system is brought to 50° C. through thejacket by a heating circulator. The reaction temperature is kept at 50°C. for 1 hour. The product is then discharged. The acid number (normallybelow 30) and iodine number (between 40-44) were measured to check theacidity and percent dithiophosphoric acid. The product purity (rangingbetween 88-95%) is measured by LC-MS and NMR.

Examples 3-5 Recovery of Mineral Values from a Base Metal (Copper)Containing Ore Body

An ore body containing Cu (0.56%) is beneficiated by froth flotation. Ineach test, 1000 g of ore sample is ground for 8.5 min in a mild steelrod mill containing a 10 kg rod charge and approximately 667 ml of waterresulting in ground ore slurry with a particle size distribution ofapproximately 80% passing 106 microns Lime is added to the mill toachieve a target pH of approximately 10.5 in the flotation stage. Aftergrinding, the slurry is then transferred to a 2.5 L Denver flotationcell and water is added to adjust the solids density to 33%. The slurryis agitated at 1200 rpm in the cell. The collector is added in oneaddition at 5 g of active collector per ton of ore in the conditioningstage. In all tests, the frother used is PBM 604 frother, available fromCytec Industries Inc., USA, which is added at a dose of 30 g/t.Flotation is conducted for 9 min. The results are presented in Table 1.

TABLE 1 Cu Ore Example No* Dosage, g/t Collector type Cu Rec. % 3C 5NaDIBDTP 83.1 4 5 EA-DIBDTP 84.5 5 5 DEA DIBDTP 85.3 *C: ComparativeNaDIBDTP: Sodium salt of Diisobutyl Dithiophosphoric acid EA-DIBDTP:Ethyl amine salt of Diisobutyl Dithiophosphoric acid DEA-DIBDTP: Diethylamine salt of Diisobutyl Dithiophosphoric acid

As employed above and throughout the disclosure, various terms areprovided to assist the reader. Unless otherwise defined, all terms ofart, notations and other scientific terminology used herein are intendedto have the meanings commonly understood by those of skill in themineral and/or mining chemical arts. As used herein and in the appendedclaims, the singular forms include plural referents unless the contextclearly dictates otherwise. All numbers expressing quantities ofingredients, reaction conditions, and so forth used in the specificationand claims are to be understood as being modified in all instances bythe term “about.” Similarly, all numbers expressed in a range asindicated by the word “between” include the upper and lower limits inthe range. Accordingly, unless indicated to the contrary, the numericalparameters set forth in the specification and attached claims areapproximations that may vary depending upon the desired propertiessought to be obtained by the present invention. At the very least, andnot as an attempt to limit the application of the doctrine ofequivalents to the scope of the claims, each numerical parameter shouldbe construed in light of the number of significant digits and ordinaryrounding approaches.

Various patent and/or scientific literature references have beenreferred to throughout this application. The disclosures of thesepublications in their entireties are hereby incorporated by reference asif written herein. In the case of conflicting terms, the terms of thisdocument will prevail. In view of the above description and theexamples, one of ordinary skill in the art will be able to practice theinvention as claimed without undue experimentation.

Although the foregoing description has shown, described, and pointed outthe fundamental novel features of the present teachings, it will beunderstood that various omissions, substitutions, and changes in theform of compositions, as well as the uses thereof, may be made by thoseskilled in the art, without departing from the scope of the presentteachings. Consequently, the scope of the present invention should notbe limited to the foregoing discussion, but should be defined by theappended claims.

What is claimed is:
 1. A froth flotation process for recovering at leastone value mineral from a mineral ore body, the process comprising:adding a beneficiating amount of a collector to at least one stage of afroth flotation process, wherein the collector comprises a primary orsecondary organic ammonium salt of a sulfur-containing acid selectedfrom the group consisting of hydrocarbyl dithiophosphoric acids,hydrocarbyl monothiophosphoric acids, mercaptobenzothiazoles,hydrocarbyl xanthic acids, hydrocarbyl thioglycolic acids andhydrocarbyl trithiocarbonic acids, thereby recovering said valuemineral.
 2. A froth flotation process according to claim 1, wherein theorganic sulfur-containing collector is an ammonium salt according toFormula I:

where: AN— is an anion from an organic sulfur-containing acid selectedfrom the group consisting of hydrocarbyl dithiophosphoric acids,hydrocarbyl monothiophosphoric acids, mercaptobenzothiazoles,hydrocarbyl xanthic acids, hydrocarbyl thioglycolic acids andhydrocarbyl trithiocarbonic acids; R^(a) is a hydrocarbyl groupcomprising from 1 to 16 carbon atoms, optionally substituted with a —OHgroup and/or with one or more —(YR′)_(n)—YR″ groups, wherein n=0 to 3, Yis O, NR′″ or S, R′ is an alkylene or arylene group containing from 1 to12 carbon atoms, R″ and R′″ are, each independently, hydrogen or ahydrocarbyl group containing from 1 to 12 carbon atoms ; and R^(b) ishydrogen or a hydrocarbyl group comprising from 1 to 16 carbon atoms,optionally substituted with a —OH group and/or with one or more—(YR′)_(n)—YR″ groups, wherein n=0 to 3, Y is O, NR′″ or S, R′ is analkylene or arylene group containing from 1 to 12 carbon atoms, R″ andR′″ are, each independently, hydrogen or a hydrocarbyl group containingfrom 1 to 12 carbon atoms; and wherein R^(a) and R^(b) may be linked toform a cyclic compound.
 3. A froth flotation process according to claim2, wherein R^(a) is an alkyl group containing 1 to 10 carbon atoms.
 4. Afroth flotation process according to claim 2, wherein R^(b) is hydrogenor an alkyl group containing 1 to 10 carbon atoms.
 5. A froth flotationprocess according to claim 2, wherein each of R^(a) and R^(b) isindependently chosen from an alkyl group containing 1 to 4 carbon atoms.6. A froth flotation process according to claim 1, wherein the organicsulfur-containing acid is selected from the group consisting ofhydrocarbyl dithiophosphoric acids, hydrocarbyl monothiophosphoric acidsand hydrocarbyl xanthic acids.
 7. A froth flotation process according toclaim 6, wherein the organic sulfur-containing acid is a hydrocarbyldithiophosphoric acid.
 8. A froth flotation process according to claim1, wherein the organic ammonium salt is selected from the groupconsisting of methylammonium, ethylammonium, propylammonium,butylammonium, ethanolammonium, diethanolammonium, propanolammonium,dipropanolammonium, dimethylammonium, diethylammonium, dipropylammonium,dibutylammonium, ethylenediammonium, 1,3-diammonium propane,hexamethylene diammonium, diethylenetriammonium, and diphenylammoniumsalts.
 9. A froth flotation process according to claim 1, wherein theorganic ammonium salt of a sulfur-containing acid is selected from thegroup consisting of dimethylammonium salt of diisobutyl dithiophosphoricacid, ethylammonium salt of diisobutyl dithiophosphoric acid,diethylammonium salt of diisobutyl dithiophosphoric acid,diethanolammonium salt of diisobutyl dithiophosphoric acid,diethylammonium salt of isobutyl xanthic acid, methylammonium salt ofmonothiophosphoric acid, dimethylammonium salt of diisobutylmonothiophosphoric acid, methylammonium salt of ethyl xanthic acid,methylammonium salt of isoamyl xanthic acid, ethylammonium salt of butyltrithiocarbonic acid, dimethylammonium salt of butyl trithiocarbonicacid, methylammonium salt of butyl thioglycolic acid, dimethylammoniumsalt of isopropyl xanthic acid, dimethylammonium salt ofmercaptobenzothiazole, ethylammonium salt of mercaptobenzothiazole,hexamethylene diammonium salt of mercaptobenzothiazole, anddiethanolammonium salt of mercaptobenzothiazole.
 10. A froth flotationprocess for recovering at least one value mineral from a mineral orebody, the process comprising: adding a beneficiating amount of acollector to at least one stage of a froth flotation process, whereinthe collector comprises a primary or secondary organic ammonium salt ofa C₁-C₅ hydrocarbyl dithiocarbamic acid, thereby recovering said valuemineral.
 11. A froth flotation process according to claim 10, whereinthe organic sulfur-containing acid is a C₂-C₅ hydrocarbyl dithiocarbamicacid.
 12. A froth flotation process according to claim 10, wherein theorganic ammonium salt is selected from the group consisting ofmethylammonium, ethylammonium, propylammonium, butylammonium,ethanolammonium, diethanolammonium, propanolammonium,dipropanolammonium, dimethylammonium, diethylammonium, dipropylammonium,dibutylammonium, ethylenediammonium, 1,3-diammonium propane,hexamethylene diammonium, diethylenetriammonium, and diphenylammoniumsalts.
 13. A froth flotation process according to claim 10, wherein theprimary or secondary organic ammonium salt of a sulfur-containing acidis selected from the group consisting of dimethylammonium salt ofdiethyl dithiocarbamic acid, diethylammonium salt of diethyldithiocarbamic acid, ethylammonium salt of diethyl dithiocarbamic acid,hexamethylene diammonium salt of N-propyl N-ethyl dithiocarbamic acid,and diethanolammonium salt of N-allyl, N-ethyl dithiocarbamic acid. 14.A froth flotation process according to claim 1, wherein the collector issubstantially water free.
 15. A froth flotation process according toclaim 1, wherein the beneficiating amount of the collector is added inan amount between 0.5 and 500 grams per ton of ore.
 16. A frothflotation process according to claim 15, wherein the beneficiatingamount of the collector is added in an amount between 1 and 200 gramsper ton of ore.
 17. A froth flotation process according to claim 1further comprising intermixing one or more additive selected from thegroup consisting of hydrocarbon oils, surfactants, aliphatic alcohols,glycols, glycol ethers, and non-aqueous solvents.
 18. A froth flotationprocess according to claim 1, wherein the at least one stage of thefroth flotation process is selected from the group consisting of aflotation stage, a grinding stage, a conditioning stage, and thepre-grinding stage.
 19. A froth flotation process according to claim 1,wherein the at least one value mineral is selected from the groupconsisting of copper, cobalt, lead, zinc, nickel, molybdenum, gold,silver, and platinum group metals.
 20. A froth flotation processaccording to claim 19, wherein the platinum group metal is platinum orpalladium.